Method and apparatus for treating plastic material



3 Sheets-Sheet 1 III lllllllllllullllll III. |||l i INVENTOR ATTORNEYSept. 21, 1937. D. s. BAKER METHOD AND APPARATUS FOR TREATING PLASTICMATERIAL Filed Feb. 27, 1954 Sept. 21, 1937. s, BAKER 2,093,407

METHOD AND APPARATUS FOR TREATING PLASTIC MATERIAL Filed Feb. 27, 1934 3Sheets-Sheet 2 INVENTOR ATTORNEY D. S. BAKER Sept. 21, 1937.

METHOD AND APPARATUS FOR TREATING PLASTIC MATERIAL Filed Feb. 27, 1934 3Sheets-Sheet 3 hm IN H INVENTOR M4 73% ATTORNEY Patented Sept. 21, 1937ME'rnon AND APPARATUS FOR TREATING PLASTIC MATERIAL David S. Baker,Greenwich, Conn. Application February 27, 1934, Serial No. 713,111

.22 Claims. (01. 25'l6) This invention relates to a method and apparatusfor treating plastic material.

More particularly, the invention relates to a method and means forconverting into uniform andmeasured form material which in some stage ofits treatment is lumpy, wet, slimy, slippery,

' tacky, or otherwise constitutes a mass which is diflicult, and in manycases disagreeable, to manipulate. One of the several fields of use thatare particularly contemplate for my invention is the preparation ofpaint pigments, such as lithopone, white lead, dry colors, insecticides,gypsum, etc., wherein a mass of wet, colored and highly adhesivematerial is produced in vats and presses and must be transformed into adry and pulverized form. One of the chief difiiculties encountered intreating such materials is their sticky or tacky nature which makes themtend to adhere to whatever comes in contact with them.

Heretofore lumps of such material have been shovelled into trays and anattempt made to level olf the mass with hand paddles or trowels, and thetrays thereafter placed in racks to Because the hand-loaded trays didnot contain a uniform amount of material, the time required it therefromby means of scrapers.

for drying each tray was by no means uniform. The operations of handloading the trays and drying have consumed an altogetherdisproportionate amount of time, and have limited the production of manyplants to an amount far below the capacity of other departments.

Furthermore, the material near the edges of the trays dries much morerapidly than that at the center of the trays, thereby causing thematerial near the edges to become overbaked. This is a distinctdisadvantage since many of the materials in the treatment of which Icontemplate using my invention, such as dry colors for example, aredefinitely weakened and impaired by overbaking.

For a long time attempts have been made, Darticularly in the chemicalindustries, to develop a practical mechanical way of handling a mass ofsuch material. and loading it uniformly into trays or other recevingmeans for drying. It has been realized that by so dong, the drying timeas wellas the loading time would be enormously decreased, and thequality of the final dry product would be improved. Attempts have beenmade to extrude such materials between cooperating rolls, and toseparate These attempts. however, have been failures because thematerial adheres to and builds up upon the My invention overcomes thedifiiculties which 5 have heretofore prevented the automatic handling oftacky plastic materials; My method of handling such materials involves,first, the molding of the material, second, the severing of the molded'material from the surfaces against which it is molded, third,distributing the molded'material in a uniform manner, fourth, subjectingthe uniformly distributed molded material to a drying gas such as heatedair, and, finally, pulverizing the dried molded material. I am, ofcourse, aware that many sorts of plastic materials have been molded forvarious purposes, but,-so far as I am aware, molding has not beenincluded as a step in any process for putting material into pulverizedform, nor has the step of severing a 20 molded material from a moldingsurface been included in the known process of molding. I My inventionincludes also automatic apparatus for continuously carrying out thismethod of handling tacky plastic materials. The appa- 25 ratus, in onepractical embodiment, includes two endless molding surfaces and areceiving surface,

all continuously moved in timed relation to one another, and means forsevering the molded material from each of the molding surfaces. The 30molding surfaces are most conveniently formed as the surfaces of twoadjacent cylinders rotated in opposite directions, while the receivingsurface is horizontal and moves under the lowest point of one of thecylinders. The tacky material is supplied between the cylinders, and ismolded between them at the point where their surfaces most closelyapproach each other. A severing 'means, such as a wire, is located closeto one of the cylindrical surfaces just beyond this point to 40 severthe molded material, or the greater part of it, from this cylinder andto allow it to travel along on the surface of the other cylinder towhich it adheres. A second severing means, such as a wire, is locatedadjacent to the surface of this cylinder at or near the lowest point ofthis surface to sever the molded material. or the greater part of it,from this cylinder and to permit it to fall without change of form uponthe receiving surface which is moving under this cylinder atsubstantially the same speed as that of the peripheral surface of themolded material on the cylinder.

An important feature of the invention cons sts in providing means forforming air spaces in the molded material to facilitate its drying.These spaces most desirably, although not necessarily, extend completelyacross the molded material so that the molded material is given the formof a series of separate, spaced, long, narrow bars. The means forforming these air spaces is a series of vanes or mold sides which areautomatically projected from one of the cylindrical mold surfaces whilethe material is being molded against this surface, and are withdrawnwithin this surface before the molded material on the surface reachesthe severing wire by means of which it is separated from this surface.

Other features/ and advantages of the invention will be pointed out inconnection with dedetailed descriptions of.a number of forms ofpractical apparatus embodying the invention, which are shown in theaccompanying drawings in which:

Fig. l is a diagrammatic side elevation, partly in section showing oneform of apparatus embodying my invention;

Fig. 2 is a front elevation of the mold member shown in Fig. 1, partlyin section;

Fig. 3 is an end view on the line 3--3 of Fig. 2;

Fig. 4 is a detailed view showing the removal of the molded bars fromthe member shown in Fig.

Fig. 5 is a vertical section of the modified apparatus adapted to load.the molded bars into trays;

Fig. 6 15a vertical section showing another embodiment of the invention;

Fig.7 is a vertical section taken |'l of Fig. 6;

Fig. 8 is a top plan view of a portion of the formed material afterleaving the device illustrated in Figs. 6 and 7;

Fig. 9 is a vertical section showing a further modification of theinvention.

The apparatus shown in Figs. 1 to 4 includes two cylinders 2, 3, and atraveling platform 21. By a common driving means not shown in thedrawings, the cylinder 2is continuously rotated on the line in aclockwise direction, the cylinder 3 in an anti-' clockwise direction,and the platform 21 is continuously moved towards the right. Theadiacent upper quadrants of the two cylinders are enlie close to thesurface of the cylinder 2 just below the point at which the twocylinders are closest to each other.

The periphery of the cylinder 3 is formed by a number of cross-members 6which rest in seats I provided therefor on the ends 8 of the cylinder 3.Within the periphery of the cylinder 3 are a number of vanes 9 ofsubstantially the width of the spaces between thecross-members 6. Eachof the vanes 9 has a cam roller i mounted in a cam race II, which is soformed that each vane is projected beyond the periphery of the cylinder3 shortly-after it enters the hopper .l, and is retracted into the spaceprovided between two of the cross-members 6 shortly before it reachesthe lowermost point of the cylinder 3, so that it may pass under thesevering wire 25. When the vanes 9 are projected beyond the periphery ofthe cylinder 3, they constitute with the periphery of the cylinder 3 anumber of long, narrow, threesided molds.

The cylinder 2 is'also provided with movable vanes 2i whose function isto force the material in the hopper into the molds carried by thecylinder 3. The vanes 2| have cam rollers 22 mounted in a' cam race 23,which is formed to project each vane beyond the surface of the cylinder2 shortly after it enters the hopper I, and to retract it just before itreaches the point at which the two cylinders are closest to each otherso that it may pass under the severing wire. 24. r

The vanes 2i are spaced far enough apart to prevent any lumps in thematerial supplied to the hopper from bridging across between them.Thespace between the vanes 9 may be less, and is preferably about equalto the height of the vanes when projected and very much less than thelength of the cylinders.

In the operation of the apparatus described, the vanes 2i of thecylinder 2 engage the material in the hopper and forcibly introduce itinto the three-sided molds formed by the vanes 9 and the periphery ofthe cylinder 3. When each mold reaches the point at which thecylinders-are closest together, the peripheral surface of the cylinder 2closes the top of the mold and molds the outer surface of the materialin it. At this point, the material in the mold, because of its tackynature, adheres to all four sides of the mold- The material in the moldis then brought. in contact with the severing wire 24, which severs it,or the greater part of it, from the surfaces of the cylinder 2. Somesmall part of the material may pass under the wire and travel around onthe surface of the cylinder 2 by which it is returned to the hopper.

As each part of molded material, after being severed from the surface ofthe cylinder 2, travels down on the surface of the cylinder 3, it isfreed from the mold sides or vanes 9 by the retraction of these sideswithin the peripheryof the cylinder 3. Because of the tackiness of thematerial,

each molded bar continues to adhere to the peripheral surface of thecylinder latter the retraction of the mold sides adjacent to it until itencounters'the severing wire 25, which severs the inner surface of thebar from the peripheral surface of the cylinder 3 and permits it .todrop on the traveling platform 21. A smallpart of the material of eachbar may pass under the wire, 25 and continue to adhere to the surface ofthe cylinder 3, in which case it is returned to the hopper by thissurface.

As the traveling platform is at only a short distance below the'lowestpoint of the cylinder 3, thebars are received on the platform withoutmaterial change of form. The platform is most desirably driven at aspeed equal to the peripheral speed of the outer surface of the moldedbars on the cylinder 3, so that the speed of move-' ment of the bars andthe spacing between them is the same on the platform as on the cylinder.

The modified apparatus shown in Fig. 5 provides for loading the tackymaterial into a series of separate trays. This figure shows abuttingtrays carried by the moving platform 21 under the cylinder 3. To avoiddepositing any of the molded bars on the abutting ends of the trays 55,the cylinder 3 isprovided with a vane 9a, which has a width slightlygreater than the width of the-abutting ends of the two trays, so thatanextra space is provided between the two bars are so related that duringone revolution of the cylinder 3 the platform moves a distance equal tothe length of one tray. To attain thisrelation and, at the same time,make. the rate of movement of the platform equal to the rate of movementof the molded bars on the cylinder, each tray-is of a length equal tothe circumference of the cylinder measured along the outer surfaces ofthe .molded bars. The trays may,

' however, be made of a length equal to any aliquot part of thecircumference of the cylinder and a plurality of wide vanes like thevane 9a may be provided in equally spaced positions around the cylinder.H

In Figs. 6, 7, and 8, a modification of my invention is shown adapted toform the material into a continuous strip or mat having a number of airspaces evenly distributed therein. To accomplish this result, a formingmember 30 is used which is provided with a continuous or unitaryperiphery 3| perforated by a number of openings 32 which may be formedby asimple stamping operation, and the openings 2 are uniformly spacedapart and staggered with respect to one another. Vane members 33 areprovided which are adapted to project through the spaces 32 provided inthe periphery 3| of the forming member 30.- The movement of the I vanesmay be controlled by cams mounted in a cam race as fully described inconnectionwith the vanes on the member 3 of Figs. 1 and 5.

As illustrated .in Fig. :6, the material is positively pressed onto theforming member 30 by any suitable means such as the member 2 fullydescribed in connection with Figs. 1 and 5, while the ends of the vanemembers 32 are projecting through the apertures 3|, and are moldedaround said projecting ends. The ends of the vanes are then withdrawn,leaving the material perforated with a uniform pattern of air spaces 34,as illustrated in Fig. 8.

The continuous strip or mat of material is separated from the formingroll by the wire 25 which is positioned adjacent the lower surface ofthe roller and extends longitudinally thereacross, as illustrated inFig. 5.

In Fig. 9 another form of forming device is illustrated comprising 'anouter cylindrical member 50 having a number of apertures 5| evenlyspaced around its periphery, and an internal rotary member 52 having anumber of projections 53 thereon adapted to register successively withthe apertures 5|. member 52 with respect to the member 50 is suchthatthe projections 53 will extend through the apertures "5| while thematerial is being fed to the forming member, and, after the formingoperation, will be withdrawn within the periphery of the member 50before the formed material ap-,- proaches the wire 25 stretchedlongitudinally across and adjacent to the member) 50 by which the formedmaterial is cut off onto the trays 55, as illustrated, or onto any othersuitable means.

-In conjunction with the member 50, the feeding ,member 56 is shownhaving modified vanes 51 pivoted thereon by the pivots 58. The members51 are controlled by the arms 51a, each having a cam roller 59 mountedin a cam race 60 by which said members 51 are caused to project throughapertures 6|, during a portion ofeach rotationof the member 50, and arewithdrawn pivot 58.

The size and position of the so that the outer ends of said members 51will be flush with the surface of the member 50 dur ing the remainingportion of each rotation of said member. It will be noted that the freeends of the members 51 are arcuate in form, all points of the are beingan equal distance from the This structure has the advantage ofpermitting the members 51 to entirely fill the apertures 6|, regardlessof the position of the members 51, thereby preventing the material fromentering the member 55 through the apertures BI.

In the modifications illustrated, the severing means is shown as a wireof circular cross-section. In practice, I have found a steel piano wirea most satisfactory severing means. The expression wire as used herein,however, should not be understood as limited to wire of any particularsize or cross-sectional shape, as any form of wire or small bar nothaving a sui liciently extended surface to cause the tacky material tobuild up as it does on a scraper may be used as the severing means andis, for this purpose, equivalent to the round wire illustrated.

What I claim is:'

1. Apparatus for handling dyes, colors, intermediates and the likematerial, comprising a rotated cylinder, a traveling platform passingunder said cylinder and moving in the same direction and atsubstantially the same speed at the lowest point of the periphery ofthe'cylinder, means for molding the plastic material against theperipheral surface of said cylinder at a distance from its lowest point,and a wire adjacent to the peripheral surface-of said cylinder near itslowest point for diverting the molded material from the surface of thecylinder to the platform.

2. Apparatus for handling dyes, colors, intermediates and the likematerial, comprising two adjacent cylinders rotated inoppositedirections to mold the said material between them at their closestpoint, and two wires, one located adjacent adjacent cylinders, a hopperfor the plastic material enclosing the upper adjacent quadrants of saidcylinders so that said material is molded between said cylinders attheir closest point, a moving platform extending under one of thecylinders,

a wire extending adjacent to the surface of the second cylinder justbelow the closest point of the cylinders to sever the molded materialtherefrom, and a wire extending adjacent to the surface of the firstcylinder near its lowest point to sever the molded material therefromand direct it upon said platform. 7

4. In apparatus for handling tacky plastic ma.- terial, the combinationof a rotary cylinder, means for supplying the material to a partoftheperipheral surface of said cylinder, :3. wire extending adjacent toanother part of the peripheral surface of said cylinder to sever themolded material therefrom, longitudinal vanes projectable through thesurface of said cylinder, and means for projecting each vane when itreaches the'part of the surface to which the material is supplied andfor reti'acting it before it reaches the wire;

5. Apparatus for handling tacky plastic matefor the material enclosingthe adjacent upper quadrants of the cylinders, a severing wire extendingadjacent to the surface of the feeding cylinder just below the closestpoint of the cylinders, a second severing wire extending adjacent to thesurface of the molding cylinder near the lowest point thereof, a seriesof longitudinal mold-forming vanes projecting from the surface of themolding cylinder within the hopper, a series of feeding vanes projectingfrom thesurface of the feeding cylinder within the hopper, means forretracting each feeding vane before, it reaches the first severing wire,and means for retracting each molding vane before it reaches the secondsevering wire. j

. 6. Apparatus for preparing tacky plastic material for pulverizing,comprising two cooperating members, said members together having fourmolding surfaces, means for withdrawing two of said molding surfaces,and wires brought between said material and each of said two remainingsurfaces respectively to separate the molded material therefrom.

'7. In an apparatus for preparing plastic material to be pulverized, amember having three molding surfaces, a second member positioned at apredetermined distance from said first member and having a fourthmolding surface, means for withdrawing three of said surfaces,-- and awire adjacent said fourth surface for separating the material from saidfourth surface. I

8. In an apparatus for preparing plastic material to be pulverized, amember having three molding surfaces, a second member positioned at apredetermined distance from said first member and having a fourthmolding surface, a wire for separating the material from said fourthmolding surface, means for withdrawing two of the mcflding surfaces onsaid first member, and a second wire 'for separating the material fromthe third molding surface of said first member.

9. In an apparatus for preparing plastic material to be pulverized, amember having three mold-- ing surfaces, 9. second member positioned ata predetermined distance from said first member having a fourth moldingsurface, and means on said second member for directing material betweenthe three molding surfaces on said first member;

10. In an apparatusfor preparing plastic material to be pulverized, alongthree-sided mold with open ends'and a member adapted to pressmaterial into said three-sided mold and'thereafter to mold the fourthsurface of the material in said three-sided mold, and means for separat--1ng the material from, both said mold and said member.

11. Apparatus for loading tacky plastic material, comprising a series ofadjacent trays, means for continuously moving said series of trays, a

rotary cylinder above said trays having a circumference equal-to anintegral multiple of the length of tray, means for molding the materialagainst said cylinder, means for separating the molded material fromsaid cylinder and diverting it into' 10 said member aroundsaid-projections, means Winn-Mas.

for withdrawing said projections leaving. air spaces in the material,and means for separating the continuous matpf material from said formingsurface without modifying the form of said mat or of the air spacesformed therein by the withdrawal of the said projections.

13. Apparatus for transforming plastic material into a continuous mat ofpredetermined depth and width, comprising a rotary cylindrical memberhaving a number of projections arranged in staggered relation around itsperiphery, means for withdrawing said projections within the peripheryof said member, means for pressing material on to said member, a wirefor diverting material from said pressing means on to said member, and asecond wire for separating the continuous mat of uniform material fromsaid member.

14. Apparatus for transforming plastic material into a continuous mat ofpredetermined depth and width, comprising a rotary cylindrical memberhaving a number of projections arranged in staggered relation around itsperiphery, means for withdrawing said projections within the peripheryof said member, a second rotary,

distance from said first member, and means on said second member forpressing material on to said first member, means for withdrawing saidpressing means while the projections on said first member are stillextended, a wire for diverting material from said second member to saidfirst member, and a second wire for separating the continuous mat ofuniform material from said first member.

15; Apparatus for preparing plastic material for pulverizing, comprisingan outer rotary drum having a number of spaced openings therein, aninternal, member having a number of p'rojections thereon adapted toregister successively with the spaced openings in said drum and toproject therethrough during part of each'rotation of said rotary member,means for supplying material to said drum while the projections on saidinner member are projecting through the openings provided therefor, anda wire for cutting said material from said drum whenthe projections onsaid internal member are not projecting beyond the surface of said drum.

16. Apparatus for preparing plastic material for pulverizing, comprisinga mold, and means for directing said material into the mold comprising arotatable cylinder having openings in its periphery and members pivotedadjacent said openings and adapted to substantially close said openingsat all times although projecting beyond the periphery of the cylinderduring a portion of each rotation of the cylinder.

17. Apparatus for preparing plastic material for pulverizing, comprisinga mold, a member having openings in its periphery, means pivotallymountedin said openings for directing material into said mold, and meansfor moving said'pivoted means on their pivots to project and withdrawsaid mold directing means in advance ofthe point of closest approachbetween said cylinder and said mold.

18. The method of transforming a mass of wet dye, color, and the likeinto pulverized form, which comprises molding the material against asurface, interposing a wire between the molded material and saidsurface, and moving the wire and surface relatively to separate themolded material from said surface, and distributing it uniformly,exposing the inolded material to a drying gas, and pulverizing the drymolded material.

19. The method of transforming dyes, color, intermediates, and the likefrom the wet tacky state in which they are received from the filterpress into pulverizing form, which comprises molding the material intoelongated plastic bars evenly spaced apart, delivering them onto areceiving means and drying without substantially 10 changing their form.

15 the material on said surface into a number of substantially equalunits, and separating means adapted to be interposed between said moldedunits and said surface, and means for moving said separating means andsaid surface relatively to one'another.

21. The method of transferring a mass of wet dye, color, and otherfiltered plastic materials to pulverizable form which comprises moldingthe material against a surface into'a number of units, interposingsevering'means between said units and said surface and moving said meansand said surface relatively to one another, delivering the separatedmaterial onto a receiving means and drying the separated material.

22. The method of transforming a mass of wet dye, color and the like topulverizing form, which comprises molding the material in the form ofelongated parallel plastic bars, distributing the bars onto receivingmeans and subjecting the bars to a drying gas.

DAVID S. BAKER.

